Electromechanical transducer for tuning individual strings of a musical instrument

ABSTRACT

An electromechanical transducer for converting the movements of a vibrating string into electric vibrations for use in tuning the string and provided with a forked member which may be clamped between two strings and converts the vibrations of a third string.

United States Patent Van Der Woerd 1 July 11, 1972 541 ELECTROMECHANICALTRANSDUCER [56] References Cited FOR TUNING INDIVIDUAL STRINGS OF UNITEDSTATES PATENTS A MUSICAL INSTRUMENT 3.|83.76l 5/1965 Van Ooyen .54/455Inventor: Albums Cormlis Van Der Wwd, Delft. 2.628.343 2/1953Murray........ ...s4/1.15 x Netherlands 3.113.990 12/1963 Zanessiv11411.16

3.265.992 8/l966 Pleasure ..s4/1.15 x [73] Assignee: U.S. PhilipsCorporation, New York. NY. 3,539,700 ll/l970 Johnson t ..84/l.|5 X2.539.297 1/1951 De Lazaro 84/116 2,725,778 12/1955 Cronwell ...84/i.163 App]. No 39.339 3,0l8,680 [/1962 Paul 84/116 Primary Examiner-Ixwis H.Myers 1301 Foreign Application Priority um f lz zg z gf Nov. 27. 1969Netherlands ..69l7828 ABSTRACT 52 u.s.c1 ..84/455,84/l.l5,84/l.l6, Anelectromechanical transducer for convening the move ments of a vibratingstring into electric vibrations for use in [5| 1 ll!- Cl. tuning theString and P i with a forked member which 58 new ofSearch ..a4/1.14.1.15. 01c. 18. DIG. 24, may be clamped between two Strings and comm thevibm tions of a third string.

PATENTEDJuL 1 1 1972 ELECTROMECHANICAL TRANSDUCER FOR TUNING INDIVIDUALSTRINGS OF A MUSICAL INSTRUMENT The invention relates to anelectromechanical transducer for converting the movement of a vibratingstring into electric oscillations, in particular for tuning the string.

Such transducers are known, for example, in electric guitars, in whichthe spring vibrates relative to the pole pieces of an electromagneticsystem. Thus, the other strings, are not influenced by the transducer.When tuning a group of three unitonal strings in a piano, it isdesirable that during the tuning of one of the strings the two remainingstrings should be damped so as to prevent them from vibrating insympathy with the string being tuned.

For this purpose, according to the invention a forked member is providedin which the spacing between the inner surfaces of the legs of the forkis equal to, or smaller than, the spacing between the outer surfaces ofthe outer strings group of three unitonal strings. This enables thecenter string to vibrate freely in the space between the legs of thefork while the outer strings are damped.

In another embodiment of an electromechanical transducer according tothe invention, the width of each leg of the fork is greater than, orequal to, the spacing between the two facing surfaces of two adjacentstrings. This enables one of the outer strings of a group of three to betuned while the two remaining strings are damped.

According to still another embodiment, at least the free end of each legis wedge-shaped, which facilitates the attachment of the transducer tothe strings.

in a further embodiment of an electromechanical transducer according tothe invention, the outer and inner surfaces of each leg are providedwith notches extending in the direction of the length of the stringsalong the clamping lines thereof. This enables the legs of the forkedmember to be clamped more firmly between the strings, so that thetransducer is less likely to twist relative to the strings.

According to still another embodiment of an electromechanical transduceraccording to the invention, the parts of the transducing system whichcooperate with the vibrating string are located between the legs of thefork.

Embodiments ofthe invention will not be described, by way of example,with reference to the accompanying diagrammatic drawings, in which:

FIG. I shows an electromechanical transducer equipped with anelectromagnetic conversion system,

FIG. 2 shows a similar transducer equipped with an electrostaticconversion system,

FIG. 3 shows a transducer in which the forked member comprises one metalspring,

FIG. 4 shows a transducer equipped with two metal springs for anelectrostatic conversion system, and

F l6. 5 shows an electromagnetic transducer the conversion system ofwhich is turned through 90 relative to that of FIG.

FIGS 1 and 2 show an electromechanical transducer 1 which is providedwith a forked member 2 having two legs 3 and 4 which have wedge-shapedends. The spacing d, between the inner surfaces of the legs 3 and 4 ofthe fork is slightly smaller than the spacing d, between the outersurfaces of the strings 5 and 6 of a group of three unitonal strings of5, 6 and 7. As FIG. 1 shows, this permits clamping of theelectromechanical transducer about the outer strings 5 and 6, notches 8helping to prevent the transducer from twisting relative to the strings.The vibrations of the center string produce a field variation in anair-gap 9 between pole pieces 10 and 11 of a yoke 12 on which a coil 14is arranged. Voltages are induced in the coil as a result of thevibrations of the center string 7, which voltages may be taken fromoutput leads 15, if

All.

d of each le of the forked member 2 exceeds the spacin d, between theacmg surfaces of two ad acent strings 7 and In this embodiment alsonotches 8 prevent the transducer from twisting relative to the strings.Although the conversion system of FIG. I is an electromagnetic system,obviously it is also possible to use an electrostatic system of the kindshown in FIG. 2, in which the vibrating string varies the capacitancebetween two plates 16 and 17 which are connected to an amplifier 18 inwhich the capacitance variations are converted into electric voltages inknown manner. This amplifier may be an integrated circuit or a simpletransistor which may be accommodated in the transducer.

The legs of the fork may be made of a plastic material and may beintegral with the transducer in which the electromagnetic orelectrostatic system is embedded, but the legs may alternatively beU-shaped metal strings 19 having opposed arcuate portions for engagingthe strings as shown, for example, in FIG. 4.

When using an electromagnetic transducer the metal must be nonmagnetic,while in an electrostatic transducer the design of FIG. 4 only can beused in which each leg of the forked member is a separate string 20secured to the casing of the transducer 1.

In order to enable the transducer to be used for the short very tautlystretched strings for the highest tones it is desirable for the legs 3and 4 of the forked member to be made relatively and intrinsicallyresilient by a suitable choice of the elasticity or compressibility ofthe plastics material, which term in this specification includes allelastic non-metallic materials, such as polyvinyl chloride, natural orsynthetic rubber and the like, or by a suitable choice of the thicknessand the nature of the metal of the springs.

The electromagnetic or electrostatic conversion system may also beturned relative to the pole piece, for example, through as is shown inFIG. 5 for the electromagnetic system.

Other conversion systems such, for example, as a Hall element mayobviously be used also.

What is claimed is:

1. A device for use in tuning a group of at least three substantiallyequispaced parallel strings, comprising a forked member having two legswherein the spacing between the inner surfaces of the legs of the memberis at most equal to the spacing between the outer surfaces of the outerstrings of the group, the legs of the member thereby restrictingvibrational motion of the outer strings, and an electromechanicaltransducer means afiixed to the forked member for converting vibrationsof a single center string of the group into an electrical signal whilethe other strings of the group are restrained from vibration by theforked member.

2. An apparatus as claimed in claim 1, for use with more than threestrings wherein the width of each leg of the forked member is at leastas great as the spacing between the facing surfaces of two adjacentstrings of the group.

3. An apparatus as claimed in claim 1, wherein at least the free end ofeach leg of the forked member is wedge-shapped.

4. An apparatus as claimed in claim I, wherein the outer and innersurfaces of each leg are provided with notches extending approximatelyperpendicular to the direction toward which the legs of the fork extend.

5. An apparatus as claimed in claim 1, wherein the transducer is locatedbetween the legs of the forked member.

1. A device for use in tuning a group of at least three substantiallyequispaced parallel strings, comprising a forked member having two legswherein the spacing between the inner surfaces of the legs of the memberis at most equal to the spacing between the outer surfaces of the outerstrings of the group, the legs of the member thereby restrictingvibrational motion of the outer strings, and an electromechanicaltransducer means affixed to the forked member for converting vibrationsof a single center string of the group into an electrical signal whilethe other strings of the group are restrained from vibration by theforked member.
 2. An apparatus as claimed in claim 1, for use with morethan three strings wherein the width of each leg of the forked member isat least as great as the spacing between the facing surfaces of twoadjacent strings of the group.
 3. An apparatus as claimed in claim 1,wherein at least the free end of each leg of the forked member iswedge-shapped.
 4. An apparatus as claimed in claim 1, wherein the outerand inner surfaces of each leg are provided with notches extendingapproximately perpendicular to the direction toward which the legs ofthe fork extend.
 5. An apparatus as claimed in claim 1, wherein thetransducer is located between the legs of the forked member.